Time Exceeded
/in/foo.cc: In function 'int main()':
/in/foo.cc:20:13: warning: unused variable 'p' [-Wunused-variable]
long long n,p,k=0,a,f[2];
^
代码
#include<bits/stdc++.h>
const long long maxn=2,mod=1e9+7;
inline const void read(long long &a)
{
a=0;char c=getchar();
while(c<'0'||c>'9')c=getchar();
while(c>='0'&&c<='9')
{
a=(a<<1)+(a<<3)+c-'0';
c=getchar();
}
}
inline const void write(long long a)
{
if(a>9)write(a/10);
putchar(a%10+'0');
}
int main()
{
long long n,p,k=0,a,f[2];
read(n);
f[0]=1;f[1]=2;
k=1;
for(long long i=3;i<=n;i++)
{
k^=1;
a=f[k^1];
f[k]=(f[k^1]+f[k])%mod;
f[k^1]=a;
}
write(f[k]);
return 0;
}
